Thanks Chaps.
Peter, the fuselage was primed with black alclad then their gloss black. This was left to cure 24 hours then the fun bit. Alclad Airframe aluminium. That was then lightly over sprayed with polished Aluminium "hist and pist" to break the solidity and give it an unevenness to the shine....
Doug here is what the RAF site has to say about MJ250:
Spitfire Mk IX MJ250
As a living and flying memorial to these courageous and determined Spitfire pilots, Spitfire Mk LFIXe MK356 is painted to represent Spitfire Mk IX MJ250 of 601 Squadron during the Italian campaign of 1944/45. MJ250 wore the 601 Squadron code UF-Q and was unusual in that it sported a natural, polished metal, all-silver finish (as shown in the only wartime photograph that exists of the aircraft) rather than the normal European theatre grey/green camouflage worn by the other aircraft of the Squadron at this stage of the war. Exactly why MJ250 was finished in this unusual natural metal scheme is not clear, although it may simply have been a trial of an all-silver colour scheme.
Spitfire Mk LFIX MJ250 was built by Vickers Armstrong in 1943, and was fitted with a Rolls Royce Merlin Mk 66 engine. It was delivered to the RAF in October 1943 and was shipped out to the Mediterranean theatre in the SS Fort George, leaving UK in December ’43. The Air Ministry Form 78 (the movement card) for this aircraft ‘dries up’ after MJ250 arrived in theatre in early 1944 but the 601 Squadron operational records (Form 541) show that MJ250 was being flown by the Squadron from July 1944, whilst the unit was operating from the airfields at Perugia, Loreto and Fano. The aircraft was used primarily for dive-bombing operations in support of the Army’s advance up through Italy, although it also flew some bomber escort sorties. MJ250 survived the war but was then scrapped.
Ian M